1. Technical Field of the Invention
The present invention relates to starters for starting up engines and methods of assembling the starters and, more particularly, a starter with a two-shaft structure, wherein a rotary shaft of a motor and an actuating shaft of an electromagnetic switch are placed in parallel to each other and which includes a case having a reduction gear accommodating section for accommodating a reduction gear section adapted to reduce a rotational speed of a motor and a switch accommodating section for accommodating the electromagnetic switch, and a method of manufacturing the starter.
2. Description of the Related Art
Attempt has heretofore been made in the related art to provide a starter of a two-shaft type wherein a rotary shaft of a motor and an actuating shaft of an electromagnetic switch are placed in parallel to each other. The starter of such a structure is usually comprised of a first case having a reduction gear accommodating section, in which a reduction gear section adapted to reduce a rotational speed of a motor is accommodated, and a second case having a switch accommodating section in which the electromagnetic switch is accommodated, with the first ad second cases being formed in separate structures and assembled to a front housing.
In the meanwhile, another attempt has been made to provide a starter including a single case having a reduction gear accommodating section, in which a reduction gear section adapted to reduce a rotational speed of a motor is accommodated, and a switch accommodating section, in which the electromagnetic switch is accommodated, which are integrally formed in a unitary structure as disclosed in Japanese Patent Laid-Open Publication No. 2005-133606. With the starter motor of such a structure, the reduction gear section and the electromagnetic switch are unitarily assembled to the front housing. This enables the starter to have advantageous effects of further improved vibration resistance to vibration of the electromagnetic switch than that of the related art structure while achieving reduction in the number of component parts constituting the starter.
However, with the starter disclosed in the related art, only the front housing is formed with an insertion recess for positioning a lever support member, playing a role as a fulcrum of a lever, which is driven when the electromagnetic switch is turned on. This results in an issue the occurrence of extremely difficult assembling work to assemble an actuating plunger of the electromagnetic switch and the lever upon engagement thereof.
To address such an issue, attempt has been made to adopt an assembling method including assembling a clutch and the lever engaging the clutch onto the front housing on an initial stage, preparing a preassembled structure with only the plunger being brought into engagement with the lever, assembling the electromagnetic switch to the front housing while inserting the plunger to the electromagnetic switch under a status before a mold cover, covering a stationary contact of the electromagnetic switch, is fixedly secured to the case, assembling the stationary contact to the electromagnetic switch, and subsequently assembling the mold cover to the electromagnetic switch. This assembling method results in an increase in the number of man-hours involving complicated assembling steps.
For another assembling method, also, an assembling method is conceived to assemble a starter by preparing a preassembled structure of an electromagnetic switch with component parts such as a mold cover being completely assembled. With such an assembling method, however, if attempt is made to allow a joint of the plunger, protruding from the electromagnetic switch in a preassembled state, and a lever to engage each other and render a clutch and the lever to be brought into an engaging status, a plunger is caused to protrude to a forward end position due to the action of a return spring and, therefore, a lever support member is raised into a free status. No position of the lever support member is fixed, causing an issue to occur on a subsequent stage with a difficulty of assembling the lever support member to an insertion recess formed in a front housing.
Furthermore, the lever has an engagement portion, to be held in engagement with a pinion moving body, which is formed in a U-shape configuration. This configuration has a structure that is hard to be firmly jointed to the pinion moving body and, therefore, the engagement portion tends to disengage from the pinion moving body. Additionally, since no position of the lever support member is fixed as mentioned above, a difficulty is encountered on a subsequent stage to assemble the lever support member to the insertion recess formed in the front housing.